Yin and yang are ideas from ancient Chinese philosophy. They describe two opposite but connected forces in the universe. These forces work together, support each other, and help create balance. Together, they form a system where the whole is more important than the parts, and both parts are needed for balance.

In Chinese mythology, the universe began from a basic energy called qi. This energy formed the cycles of yin and yang, leading to movement, form, and matter. Yin is quiet, passive, and draws things in, while yang is active, outward, and pushes things away. These opposites are found in nature, like in the changing seasons, the growth of plants, and even in human life. For example, yin is linked to feminine traits, and yang is linked to masculine traits.

Taiji means the "Supreme Ultimate," a state before the universe was divided into yin and yang. It is the beginning of all things. This idea is different from wuji, which means a state with no clear direction. In this philosophy, qi is the energy that created the universe. It is believed that how qi is organized forms all things in the world, including humans.

Many natural opposites, like light and dark or fire and water, are seen as examples of yin and yang. This idea of opposites working together is important in many areas, such as traditional Chinese medicine, martial arts like tai chi and qigong, and ancient texts like the I Ching and the Huangdi Neijing.

In Taoist beliefs, good and bad are not real differences but are how people see things. However, Confucianism, especially in the ideas of Dong Zhongshu, adds a moral meaning to yin and yang. The Ahom philosophy, which comes from Yunnan, China, uses the ideas of yin and yang to explain the mind through the concepts of hun (yin) and po (yang). This tradition was followed by some Ahom people, who are descendants of the Dai ethnic group.

Linguistic aspects

The Chinese characters 阴 (yīn) and 阳 (yáng) are both phono-semantic compounds. This means they are made up of parts that show meaning and sound. The semantic component 阝 (mound or hill) is a graphical variant of 阜. The phonetic component for 阴 is 今 (jīn), and for 阳 is 昜 (yáng), which includes the meaning of "bright" and is made up of 日 (sun), 示 (a symbol), and 彡 (sunbeam).

The standard Chinese pronunciation of 阴 is usually the flat first tone as yīn, meaning "shady" or "cloudy." It can also be pronounced with the falling fourth tone as yìn, meaning "to shelter" or "shade." 阳 is always pronounced with the rising second tone as yáng, meaning "sunny."

Scholars have studied ancient sources, such as the Qieyun rhyme dictionary from the 7th century and the Shijing (a collection of poems from 11th–7th centuries BCE), to understand how Chinese words were pronounced in the past. These studies help explain the origins of modern Chinese words.

For example, the character 阴 (yīn) may have a similar origin to words in other languages like Burmese and Lepcha that mean "overcast" or "shade." The character 阳 (yáng) may be related to words in Lepcha and Burmese that mean "bright" or "light." Some scholars also link 阳 to other Chinese words like 昌 (chāng), meaning "prosperous" or "bright."

The words 阴 and 阳 have many meanings. In dictionaries, 阴 can refer to the female or passive force in nature, the moon, shaded areas, or the north side of a hill. 阳 can refer to the male or active force in nature, the sun, sunny areas, or the south side of a hill. Together, 阴阳 (yīnyáng) means "yin and yang," representing opposites in philosophy, astronomy, and other fields.

In geography, 阳 often means the sunny side of a mountain or the north bank of a river. For example, the city Hengyang is named for being south of Mount Heng, and Luoyang is named for being north of the Luo River. Similarly, 阴 refers to the shady side of a mountain, as in Huayin, which is north of Mount Hua.

In Japan, the characters 阴 and 阳 are used to describe regions. The San'in region (山陰) is the north side of the Chūgoku Mountains, while the San'yō region (山陽) is the south side.

In English, the words "yin," "yang," and "yin-yang" are borrowed from Chinese. The Oxford English Dictionary defines "yin" as the feminine or negative force in Chinese philosophy and "yang" as the masculine or positive force. "Yin-yang" refers to the balance of these two forces.

The earliest recorded use of "yin and yang" in English is from 1671. The term "yin-yang" became common in 1850, and "yang-yin" is sometimes used by mistake. In Chinese, the order of words in pairs like yin-yang matters. For example, "yin-yang" is different from "yang-yin," even though both words appear together. This pattern is common in Chinese, where the first word in a pair is usually more important or positive.

History

Joseph Needham explains that yin and yang, along with the Five Elements, are part of the School of Naturalists. He suggests that yin and yang should be discussed first because they are considered more fundamental principles in ancient Chinese thought. However, he notes that historical information about the Five-Element theory is better documented than that of yin and yang, so he chooses to address the Five Elements first for clarity.

Needham then describes Zou Yan (305–240 BC), who is closely linked to these ideas. Although Zou Yan’s surviving writings do not mention yin and yang, his school was known as the Yin Yang Jia (Yin and Yang School). Needham concludes that the use of the terms yin and yang in philosophical texts likely began around the start of the 4th century BC. He also states that references to these terms in older texts were added later, after that time.

Nature

Yin and yang are ideas from ancient Chinese philosophy that explain how opposite forces, such as dark and light, are connected and depend on each other. These forces are not separate but work together to create balance in the natural world. They help form each other through their relationship, showing that opposites are actually parts of a single whole.

In Daoist philosophy, the idea of yin and yang is discussed in the Tao Te Ching, chapter 42. It is impossible to describe yin or yang without mentioning its opposite, as they are always compared to each other. For example, the bottom of the foot cannot exist without the top. This shows how yin and yang are linked and cannot be understood alone.

An example to explain this is imagining a group of people who are all women or all men. Such a group would not survive because there would be no way to create new generations. However, when men and women are together, they can have children, allowing their group to continue. This is similar to how yin and yang work together to create life, just as heaven and earth work together to create harmony and bring things into existence.

Modern usage

Yin is often shown as black, and yang is often shown as white. In some cases, the white part representing yang has been replaced with red. The taijitu, also called the "diagram of the Supreme Ultimate," is sometimes shown with other shapes, such as the bagua.

The ideas of yin and yang are also used to describe the human body. In traditional Chinese medicine, a person's health depends on the balance between yin and yang qualities inside them. The study of yin and yang helps doctors diagnose illnesses by looking at the balance of these qualities in Taoist-influenced traditional Chinese medicine.

The principle of yin and yang is shown in the taijitu. This term is often used to describe the simple "divided circle" image, but it can also refer to other diagrams that represent these ideas. For example, the swastika is used in religions like Hinduism, Buddhism, and Jainism. Similar symbols have also been found in other cultures, such as in Celtic art and on Roman shields.

In the taijitu symbol, two water droplets swirl and mix. They show how yin and yang change into each other, moving from dark, murky yin to light, clear yang and back again. The droplets move in opposite directions, showing that when one increases, the other decreases. However, they are the same in size and substance, showing a balance. The small dot inside each droplet shows that yin and yang can always be divided further, meaning yin is always inside yang and yang is always inside yin. The S-shaped curve in the center shows how much yin or yang is present, like when night turns into day. Drawing a horizontal and vertical line through the center of the symbol shows how much yin and yang are present in each of the four seasons.

Tai chi is a type of martial art that uses the principles of yin and yang to describe movement in the human body and in animals. Wu Jianquan, a famous teacher of Chinese martial arts, explained tai chi (taijiquan) as follows:

Some people say the name "taijiquan" comes from the idea that training oneself starts with movement and ends with stillness. The balance of yin and yang creates taiji. In terms of fighting, movements are based on circles, like the shape of the taijitu. This is why it is called taijiquan.

— Wu Jianquan, The International Magazine of T’ai Chi Ch’üan